Since the early 1970s, it has been known that antigen-specific IgE can be recovered from nasal and bronchial secretions in allergic patients who are challenged with that antigen (Yoshida T, 2005). It has also been demonstrated that IgE can be present in nasal secretions even though skin testing (Houri M, 1972) and in vitro testing (Stenius B, 1971) are negative, and it has been suggested that this locally produced IgE can cause an inflammatory reaction in a specific part of the airway, without affecting the rest of the body. In 1985, Ohashi et al. demonstrated elevated IgE levels in homogenized nasal mucosa from twelve patients with symptoms suggestive of allergy who were negative on skin and RAST testing (Ohashi Y, 1985).
Local IgE production has also been recognized in the pathogenesis of such conditions as allergic fungal rhinosinusitis (Pant H, 2009) and nasal polyposis (Sabirov A, 2008). Levels of Alternaria-specific IgE in nasal polyp tissue have been found to be significantly higher than non-polyp tissue from patients with chronic rhinosinusitis, and 60% of patients with nasal polyps had evidence of local IgE without evidence of Alternaria-specific IgE in the serum (Sabirov A, 2008). In addition, local IgE may also be responsible for symptoms in patients with chronic rhinitis who are diagnosed with “non-allergic rhinitis” based solely on negative skin and blood testing (Durham S R, 2000).
Current methods to collect local IgE in the nose include nasal lavage (Yoshida T, 2005) and surgical biopsy of nasal tissues (Ahn C N, 2009). However, nasal lavage is a difficult test to perform in the office setting, particularly in the pediatric population. In addition, it is uncomfortable for the patient and has a high rate of technical variability, which limits the interpretation of the results. Nasal lavage specimens can only collect IgE that is present in the mucus, but there is additional IgE present in the epithelium of the inferior turbinates (Ahn C N, 2009). Surgical biopsy will detect epithelial IgE, but this is an invasive test which is not practical in the office setting or ethical to perform solely for the purpose of allergy testing.
Brush biopsy with a cytology brush has been used inside the nose for the study of ciliary ultrastructure (Rutland J, 1982) and for viral culture (Winther B, 1986), but has not been used for collecting mucosal material and antibody testing.